Apparatus and method for electrolytically depositing metals



Feb. 24. 1925. '1,527,734

N. HUGGINS APPARATUS AND IETHOD [0R ELECTROLYTICALLY DEPOSIT-ING METALS `Filed Dec. 14. 1922 JKU? Patented Feb. 24, 1925.-

vUNITED STAT s 1,521,734 PATENT OFFICE.

NATHZ'ANIEL HUGGINS, OF NEW YORK, N. Y.. ASSIGNOR '10 THE ELCTROLYTIC COR- PORATION, A CORPORATION F DELAWARE.

APPARATUS AND METHOD FOR ELECTROLYTICALLY DEPOSITING MTALS.

Application led December 14, 192B. Serial No. 606,969.

To 7l N'wm it 71mg/ concern Be it known that I, NATHANIEL HUooiNs,

a. citizen of the United States, residing in the city and State of New York, have invented an Apparatus and Method for Electrolytically-Depositing Metals, of which the following is a specification.

One object ot this invention is to provide a simple and convenient process and apparatus for obtaining electro-deposited metals of relatively high tensile strength and free from or having a minimum of occluded hydrogcnz-the invention more especially contemplating a novel method of operation which shall be highly efficient as well as adapted for the commercial production of relatively `pure metals on a large scale.

Another object of my invention is to provide the combination of an electrolytic bath having an anode and a cathode therein connected respectively to the positive and negative terminals of a direct current circuit and also connected to the terminals of a uni-directional, pulsating circuit. l Other objects and applications of my invention, as well as details of construction and operation, will appear more fully from the following description and claims, when taken in connection with the accompanying drawings, wherein:

The single figure of the drawing is a diagrammatic view of circuits and apparatus embodying my invention.

In carrying out my invention I provide a r solution which may be a metallic salt, such for example as ferrous chloride of any suitable concentration, e. g.. four and one-half pounds of ferrous chloride to one gallon of water. This solution 1 is placed in a suitable container 2 with two electrodes 3 and 4, of which that commonly designated the anode say 3, may be either soluble or insoluble iron such as scrap iron. although if desired I may in place of an iron anode employ one of steel. The electrode ordinarily designated the cathode say 4` may be of any suitable conducting material such as a body of lead having a form suitable to receive the electro-deposited metal. In accordance with my inventiomthe electrodes 3 and 4 are connected primarily in a direct current circuit 5, which may also include a source of direct-current energy 6,the voltage of the latter depending upon the composition and concentration of the solution 1 and alsoupon the spacing of the electrodes 3 and 4 as well as on the current density per square foot of electrode surfa`ce;-being in a typical case four volts. Thereafter. further in accordance with my invention, I connect said electrodes 3 and 4 to a` suitable source of uni-directional pulsating electric current 7 such as a current rectifier 8 'connected in series-circuit relation with the secondary winding 9 of an alternating current transformer 10. It is particularly noted that in accordance with my invention, the positive terminal of the circuit in which the uni-directional pulsating current flows is to be connected to that particular electrode of my device which is connected to the negative terminal of the direct current circuit 5, i. e.,-the cathode 4 of the bath, while the second terminal of the pulsating circuit is obviously connected to the anode 3 of the-bath.

With a direct current ordinarily having .a drop of four volts between the electrodes 3 and 4 and a current density of approximately 180 amperes per square foot of 80 cathode surface, I have successfully deposited metal of a high grade on the cathode, using a. uni-directional, pulsating current obtained from an alternating circuit having a frequency of 500. Under these conditions the current delivered by the current recti- .fier was approximately between 71/2 and 15 volts at 4 to 51/2 amperes, while the voltage between the electrodes 3 and 4 fell to approXimately one volt.

Under conditions abo-ve described I have found that the metal deposited on the cathode 4 is closer grained, of a higher tensile strength and contains less occluded hydrogen than that ordinarily obtainable by electrolytic deposition, being especially adapted for those usesrequiringrelatively pure iron of a high grade.

It is particularly to be noted that the above process is carried out at normal tem- 100 peratures, that is to say, the electrolyte is preferably at a temperature of from 70 to F., although no objectionable results are noted if the temperature should for any reason increase above the latter point. 105

My invention may be advantageously used not only for the electro-deposition of iron but also forobtaining, from electrolytes containing copper, zinc and the precious metals such as gold and silver, 'these metals z-the ,110

anode and cathode in anycase being connected in a direct current circuit and being also respectively connected to the negative and posltive terminals of a suitable source of uni-directional, pulsating current, as shown, for example, 1n the single figure of the drawing.

I claim:

1. The method of electro-deposition which consists in subjecting a solution simulta ,neously to the action of a. direct current and also to the actionof a uni-directional, pulsating current.

2. The method of electro-deposition which consists in subjecting a solution of a metallic salt simultaneously to the action of a direct current and also to the action of a uni-directional, pulsating current.

3. The method of electro-deposition which consists in passing a direct current from an anode through a solution to a cathode and at the same time causing a uni-direc tional, pulsating current to How from said and an opposed uni-directional, pulsating current.

5. The combination of an electrolytic bath having an anode and a cathode therein connected respectively to the positive and negative terminals of a direct current circuit and also connected to the terminals of a unidirectional, pulsating circuit.

6. The combination with an electrolytic bath having an anode and a cathode, of a direct current source having its positive and negative terminals connected respectively to said anode and cathode; with a current rectifier connected in an alternating circuit and having its positive terminal connected to the cathode and its negative terminal connected to the anode.

NATHANIEL HUGGINS. 

